ABSTRACT
Transformer operation is based on the principle of induction discovered by Faraday. This chapter focuses on larger power transformers. Transformers are necessary to convert the high voltages to lower levels at the receiving end. They are also necessary at the sending end of the line to boost the generator voltage up to the required transmission levels. Transformer voltages can be adjusted by equipping transformers with tap changers, which are devices that add or subtract turns from a winding, thus altering its voltage. Transformers are fairly passive devices containing very few moving parts, which include the tap changers and cooling fans used in most units and pumps used in oil-filled transformers to improve cooling. The chapter explores the basic difference between core-form and shell-form transformers. In larger power transformers, stacked cores are more common, whereas in small distribution transformers, wound cores predominate. The chapter describes the methods of winding the coils for core-form power transformers: disk coil and layer coil.
